Common ownership,market power,and innovation

I examine the effects of overlapping ownership on market power when there are external effects across firms. This is done in an oligopoly model with cost-reducing innovation with technological spillovers where firms have an overlapping ownership structure based largely on López and Vives (2019). The model allows for Cournot competition with homogeneous product and for Bertrand with differentiated products as well as for strategic effects of R&D investment. It derives positive testable implications and normative results to inform policy.